var nav_off = new Image();
var nav_on  = new Image();
var nav_ani = new Image();

function postload() {

  //if (!document.images) return true;

  nav_off.src = "images/menubox_off.gif";
  nav_on.src  = "images/menubox_on.gif";
  nav_ani.src = "images/menuanim_8x9_32c.gif";

  return true;
} // postload


function navD(imageID, lightswitch)          // big grey electical boxes
        //
        // takes two args:      imageID         the  NAME  value
        //                      lightswitch     the desired state and
        //                                      is used to build name
  {     //                                      of Image() object
  //if (!document.images) return false;

  var state  = lightswitch;
  var target = imageID;
  var source = "nav_"+state+".src";

  if (eval(source) == "") { postload(); }   // event before  postload1()  ?
  document[target].src = eval(source);
  return true;
}